Coating for de-icing aircraft



COATING FOR DE-ICING AIRfIRAFT Elmer A. Fike, Nitro, W. Va, assignor to Monsanto Chemical Company, St. Louis, Mo a corporation of Delaware No Drawing. Application November 2, 1954 Serial No. 466,450

4 Claims. (Cl. 117-161) The present invention relates to the prevention of ice accretion and more particularly to the de-icing of or prevention of ice accretion on aircraft surfaces.

High altitude and particularly winter flying especially in those portions of the world not subject to tropical and semi-tropical climates involves a most serious hazard resulting from the accumulation of ice on various parts of an aircraft. This hazard has been combatted with some success by various mechanical means but such means, unfortunately, are effective only so long as the mechanism functions in a satisfactory manner. Obviously it would be much more desirable to employ suitable and effective means to prevent the formation of ice on such surfaces rather than to rely on mechanically actuated means to remove ice that has formed.

It has now been found that treatment of those surfaces of an aircraft where the accumulation of ice is most liable to occur, such for instance as the wings, control surfaces, struts, propellers and the like, with a composition as hereinafter set forth, develops a surface to which water and sleet do not adhere and as a result of which, ice does not form nor accumulate. Moreover, the composition is simple to prepare and is easy to apply and furthermore is effective over a satisfactory period of time, although for reasons of maintaining completely safe operating conditions it is advisable to apply a new coating of the composition from time to time.

In accordance with the present invention there is applied to the surface or surfaces of the aircraft, the ice adhesion of which it is desired to lower or prevent, a layer or film comprising a sulfonated polystyrene or alkali metal salt thereof, admixed with a spreading agent and a plasticizing agent. The composition is applied in a carrier liquid and in the form of a solution of the ingredients, which, following the removal of the carrier liquid leaves a smooth hard film of uniform thickness. Inasmuch as water is the most desirable carrier liquid to utilize, it is necessary to employ a water soluble polystyrene and one such product is described and claimed in United States Patent 2,533,210 and 2,533,211 both issued December 12, 1950, to Massimo Baer. The present invention accordingly is limited to the use of a water soluble polystyrene compound, preferably an acid derivative thereof, and its water soluble mineral salts.

An example of a typical composition effective for the object previously described comprises 400 parts of water, 100 parts of ethylene glycol, 40 parts of sulfonated polystyrene, parts of poly ethylene oxy thio ether and 20 parts of sodium decyl benzene sulfonate. This composition when spread on a surface dried to form a film of sulfonated polystyrene plasticized by ethylene glycol, which latter combined with the smooth film of the poly- 2,933,419 Patented Apr. 19, 1960 rice styrene served to prevent ice from adhering to the surface thereof.

It is to be understood that the proportions of ingredients set forth are for purposes of illustration only and not in any way limitative of the invention. However, the ratios set forth are considered most desirable from the standpoint of ease of and adaptability for application to a surface. More or less of the sulfonated polystyrene than to form a 10% solution as shown may be taken, depending upon the thickness or viscosity desired in the finished composition. Likewise other plasticizing agents than ethylene glycol, provided they be water soluble, may be employed and in amounts other than of 25% by weight of the solvent. Moreover in place of the wetting agent specified, sodium decyl her one sulfonate, employed primarily to produce better spreading of the composition, other substantially salt free, water soluble wetting agents may be employed.

It is intended to cover all changes and modifications of the examples of the invention herein chosen for purposes of disclosure which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

l. A method of decreasing ice accretion on the exposed surfaces of aircraft which comprises applying to said surfaces a composition consisting essentially of a Water solution of a water soluble polystyrene, a spreading agent and a water soluble glycol as plasticizing agent and then effecting removal of the liquid carrier thereby depositing a smooth hard film which prevents ice from adhering to the aircraft surface.

2. A method of decreasing ice accretion on the exposed surfaces of aircraft which comprises applying to said surfaces a composition consisting essentially of a water solu tion of a water soluble sulfonated polystyrene, a spreading agent and a water soluble glycol as plasticizing agent and then effecting removal of the liquid carrier thereby depositing a smooth hard film which prevents ice from adhering to the aircraft surface.

3. A method of decreasing ice accretion on the exposed surfaces of aircraft which comprises applying to said surfaces a composition consisting essentially of a water solution of a water soluble sulfonated polystyrene, the said polystyrene being at least 10% by weight of the water, a spreading agent and ethylene glycol and then effecting removal of the liquid carrier thereby depositing a smooth hard film which prevents ice from adhering to the aircraft surface.

4. A method of decreasing ice accretion on the exposed surfaces of aircraft which comprises applying to said surfaces a composition consisting essentially of a. water solu tion of approximately 10% sulfonated polystyrene, substantially 25% ethylene glycol, substantially 5% sodium decyl benzene sulfonate and substantially 2.5% poly ethylene oxy thio ether, the percentages being expressed as percent by weight of the water and then effecting removal of the liquid carrier thereby depositing a smooth hard film which prevents ice from adhering to the aircraft surface.

References Cited in the file of this patent UNITED STATES PATENTS 2,031,929 Brevers et a1. Feb. 25, 1936 (Other references on following page) V- 3 Keenoy Oct. 7, 1941 OTHER REFERENCES i gfigg j $512 13:: Handbool z of Plastics, by Simonds et aL; 2nd ed. Jennings 1948 (1949), pubhshed by Van Nostrand Co. Signer July 22 1952 ,5 Styrene-Its Polymers, Copolymers and Denvatxves, SmithJohannsen No 1952 Boundy-Boyer, ACS Monograph Senes No. 115; (1952): Roth Feb 23, 1954 Published by Reinhold Pub. Corp. McDonald 24, 1954 Sulfonation Products From Polymers of Styrene and FOREIGN PATENTS Australia May 22, 1945 Vinyltoluene, by Roth; Ind. and Eng. Chem, November 10 1954, pp. 2435-2439. 

1. A METHOD OF DECREASING ICE ACCRETION ON THE EXPOSED SURFACES OF AIRCRAFT WHICH COMPRISES APPLYING TO SAID SURFACES A COMPOSITION CONSISTING ESSENTIALLY OF A WATER SOLUTION OF A WATER SOLUBLE POLUSTYRENE, A SPREADING AGENT AND A WATER SOLUBLE GLYCOL AS PLASTICIZING AGENT AND THEN AFFECTING REMOVAL OF THE LIQUID CARRIER THEREBY DEPOSITING A SMOOTH HARD FLIM WHICH PREVENTS ICE FROM ADHERING TO THE AIRCRAFT SURFACE. 